Whats wrong with my car?

Ok, last month my car started acting funny. It would drive fine through the city, but as soon as I got on the expressway the RPM gauge would shoot up to 3-4000 RPM, buck/jerk then return to normal. It would only do that on the expressway, then it started to do it a little on the street, not the jerk/bucking part, just the RPM would go up. I got a transmission flush, that didn't help at all. So I took it to another shop, they pulled the code P1702, and said I need a new transmission. I don't think that I do, it changes gears just fine, no jerking of gears, no hard shifting. So I picked it up, brought it home, called the place where I got the fluid change, they picked it up, and said I need a transmission(I STILL DON'T THINK SO!!). The first place, they wanted $2200, and the place where I got the fluid change wanted $1600...money that I do not have at all, I can't even get a loan, so that's not going to happen. So, I finally took it to a guy who said it it the TPS sensor, he changed that, and now it's worse than ever! I know I will probably get some responses telling me that I need a new car, which I can't afford, and I will probably get some jerk calling me an idiot because I didn't listen to the 1st shop I took it to, but as long as I get an answer I don't care(besides I can always flag the jerks). Someone (with sense) please help. I have a 2000 Ford Contour 2.5L with 183K miles.